Thursday 24 May 2012 16.01 EDT
First published on Thursday 24 May 2012 16.01 EDT

If Jeremy Hunt hoped the resignation of his close aide Adam Smith would draw the sting of the scandal surrounding his handling of Rupert Murdoch's BSkyB bid, his hopes would have been dashed by Smith's brief appearance before the Leveson inquiry on Thursday .

Though he spent little more than an hour in Court 73 of the Royal Courts of Justice, Smith dropped the bombshell of the day by handing to the inquiry an email from his private account which could yet sever the slim thread connecting Hunt to his cabinet job.

The email contained a draft of a remarkable memo Hunt sent to David Cameron on 19 November, after a little drafting help from Smith. The memo railed against the business secretary, Vince Cable, for moving against the BSkyB takeover bid being promoted by the Murdoch family, father and son. It nailed Hunt's own colours firmly to the mast, as a committed, even passionate supporter of the bid.

Hunt even summoned up the spirit of Margaret Thatcher and her historic Tory struggles against the unions in the 1980s, writing enthusiastically: "Essentially what James Murdoch wants to do is to repeat what his father did with the move to Wapping and create the world's first multiplatform media operator available from paper to web to TV to iPhone to iPad."

This was not quite the way News Corporation had publicly presented its bid at the time, assuring the world it had no intention of "bundling" advertising and subscriptions to create a dominant media behemoth.

More significantly for Hunt's personal political fortunes, the words of the memo are the exact opposite of the picture he has sought to present to the world, that he approached the BSkyB bid – which he became responsible for deciding from late December 2011 – in an impartial spirit.

Furthermore, Hunt had attempted to save himself by forcing the resignation of his own special adviser on the grounds that the "tone and content" of Smith's emails and texts to News Corp had gone too far, because they represented Hunt as supportive of the bid. It now seems, after the publication of the Hunt memo, that his special adviser was reflecting the contents of his master's mind with perfect accuracy. If anything, he was too mild in the way he put it.

Hunt had used strong terms in private: he told the prime minister James Murdoch was "furious" that Cable was interfering with his media plans, and that it would be "totally wrong" to "cave in" to the bid's opponents.

No one will call this language "quasi-judicial" – the term the government repeatedly used to characterise Hunt's handling of the bid after he took over responsibility for it. It is likely to appear to his critics just as biased in the other direction as was Cable when he lost his control of the bid for recklessly saying he had "declared war" on the Murdochs.

The history of events at the end of 2010, from the moment on 4 November when Cable called in the regulators, shows how relentlessly James Murdoch and his PR man Frédéric Michel lobbied and berated the politicians who were trying to stand in their way. Only three days later, Murdoch was lunching at Chequers with Cameron. The next day, Michel lunched an aide to George Osborne, the chancellor, who he hoped could be persuaded to intervene.

Cable's own advisers refused to meet any of the Murdoch camp, saying it would be improper. So did Treasury minister Danny Alexander.

Michel and James Murdoch therefore concentrated their fire on Hunt and his team at the Department for Culture, Media and Sport (DCMS), even though they had no official role in the legal process being carried out at Cable's business department. Murdoch phoned Hunt and also arranged to meet him.

Hunt caused growing dismay in his department by his apparent enthusiasm for intervening on behalf of the Murdochs. As Michel's published emails reveal, and as counsel to the Leveson inquiry confirmed on Thursday, the DCMS legal director gave him a stern warning not to meet James Murdoch or interfere in Cable's handling of the bid. While not strictly illegal, he said that it would be "unwise".

Hunt was apparently more concerned to appease Murdoch than bow to all his department's proprieties: he appears to have held a mobile phone conversation with Murdoch, although he cancelled his face-to-face meeting. Hunt was already well-briefed on Murdoch's plans: Michel had previously sent him, via his adviser Smith, a lobbying package, outlining Murdoch's ambitious plans for a multimedia breakthrough comparable in scale to his father's move to Wapping in the 1980s.

Within weeks of Hunt launching his anti-Cable campaign in Downing Street, the business secretary would fall victim to a newspaper sting in which he confided that he had "declared war" on Murdoch, and responsibility for the bid was turned over to Hunt.

Hunt's critics will now read the text of his memo to Cameron as the final nail in the coffin of his claims to have switched mentally to a "quasi-judicial" role. This will certainly increase the pressure on him to step down. But it will also raise the question of why Cameron, knowing what a committed supporter of the bid Hunt was, thought it appropriate to give him the job of deciding on it.

What is now known, thanks to the Leveson process, is that James Murdoch was considerably mollified at the time. In the runup to that Christmas, he and Cameron shared a now notorious Christmas lunch at the Oxfordshire home of News International chief executive Rebekah Brooks, in a less "furious" and presumably more festive spirit.